| This thesis is divided into two chapters. Chapter1is split into two sections. In Section1, we introduce briefly the history of queueing theory. In Section2, we first introduce sup-plementary variable technique, then we state the problem that we will study in this thesis. Chapter2consists of two sections. In Section1, firstly we introduce the exhaustive-service M/M/1queueing model with single vacations, then we convert the model into an abstract Cauchy problem in a Banach space by introducing a state space, operators and their domains, lastly we introduce the main results obtained by other researchers. In Section2, we prove that if λ<η<μ-λ+2(?)λη, then all θ(2(?)λη-λ-η) are eigenvalues of the operator, which corresponds to the M/M/1queueing model with single vacations, with geometric multiplicity one for all θ∈(0,1). |